This research is concerned with the functional properties of hemoglobin variants of known structure. The structural studies will consist of establishing the primary structure, together with the sedimentation velocity where indicated. For functional studies, O2 equilibria, the kinetics of reactions with ligands, stability to heat and inorganic solvents and gelling interactions with deoxy sickle cell hemoglobin will be observed. From these data, the role of specific amino acid residues in the functional properties of hemoglobin can be evaluated. Evaluation of glycohemoglobins in diabetes will be extended to include effects of diet on glycohemoglobin levels, and the role of glycohemoglobins in sickling interactions. Studies of the primary sequence of hemoglobin of normal rats will be continued, and extended to Belgrade rats which have an hereditary thalassemia-like anemia.